Pupillary scale



Aug' 3, 1943. W. R. HEARN v 2,326,030

PUPILLARY SCALE Filed OCT.. 18, 1940 Patented Aug. 3, 1943 UNITED` STATES PATENT OFFICE` Y n 2,326,030 h PUPILLARY SCALE e h Wimamla. Hearn, cincinnati' ohio Application octoberis, 1940,seria1N0. 361,747

(oise- 2m Y s claims. My invention relates to optical equipment, and

moreiespecially to instruments for use of optometrists in ascertaining some relation of the pupils of the eyes to each other orto some other feature of thepatient.

Onel object is to render reference of indicia of the instrument. to the pupils or other features less difficult yet to increase the accuracy of ascertainmentof the relation or -relations. A further Objectis to magnify'the pupils or other features, further to facilitate the reference and ascertainment. A further, and preferred object, is to afford a plurality of references and ascertainments of that kind, upon-one setting of the scale orinstrument. In general, the` object is to facilitate `and increase lthe accuracy `of suchmeasurements as are required to prescribe those factors entering intothe' production of eyeglasses as regards th'efmounting ofthe lenses,and aside from the optical proportions of the lensesthemselves, so that rWhenV the glasses are fitted to the patient with the lenses included-the lenses willy be-properly'related to the pupils of the. eyes for maximum correctness of vision, and will be supported to maintain proper relation of the lenses to-the eyes with full comfort tothe wearer of the; glasses. A further, and preferred, object isto make the instrument of vminimum Weight commensurate with its purpose, and yet have the .instrument amply strong and durable.

Y Other objectswill' appear in the. course of the following description, illustrated by the accommodified scale;

Fig'. 6 is a cross section on the vertical plane ofthe line 6--6 of Fig, 1;

Fig. 7 is va similar view-showing aV modified cross section; and

Fig. 8 is another similar View showing a second modified cross section..

As shown in Figs. l'to` 4, inclusive, the scale consists of a single piece of transparentmaterial, preferably the plastic material known as Lucite, which has very nearly the same properties as good optical glass and has sufficient hardness and strength towithstand Wear and-impacts, as by dropping. This pieces, as shown in Fig;A 6 is of cross section, except midway of its length, substantially `a segment of a circle; VWhile atA the midlengtn there is a recess opening out from one ofthe edges of the piece` 'Y That is to say, the scale has the portions l and 2 ofthe full segmental cross Vsection' extending in oppothe chordal or'rear side `5 is substantially plane;

- the convexityof the front side and the plane of the rear side 5 being las nearly perfect as is possible in commercial productionl andas iserequired toconstitute the piece a' prism which is an elongatedjsegmentof a cylinder. With such shape, the pieceso refracts from rear to front as to enlarge `the apparent `length of an object in the chordal direction, when the object, in back of the scale, is viewed from the front ofthe scale. This is noted in Fig. 3, Where the irises and pupils of the eyes appear elliptical with; the

major aXis of the ellipse across or in'thechordal direction. The scale being applied Ato the eyes with the axis of the segmentvappr'oximately mid- Way of the upright diameters of the irises and pupils," this aDplGXimately elliptical, not oval, appearance is ",had. l Being a 1 substantially straight'segment of a cylinder, there is substantially no magnification crossw'ise of the irises and .pupils,li." e., lengthwise of the scale.

This kind of nlagniieationY also lis had in increased degree With a substantially semicylindrical cross section'as indicated in Fig. '7; this formation beingpractical, though not preferred as it makes, the up and down length of the ellipse greater than the corresponding Width of the scale, With'soine distortion of the appearance. In Fig. Sthe convexity is that of the longest half of an ellipse, with a somewhat improved appearance of the irises and pupils as apparent ellipses; this form having merely the disadvantage of requiring more care in themaking of thev apparatusfor producing it. When made of plastic material, of which Lucite, as before mentioned, is-the preferred material, the scale is made bymolding under heat and pressure as is usual with the` various-plastics of such-nature. Other plasticsmay be used, but 'must have highly uniform refractive properties and'clear'ness; and of course glass may be used, with the disadvantages of being harder and less easily marked, and being more breakable than fL'ucite or other plastics.

Also it will be understood that anyothertransparent material having the 'above mentionedA the operators hand or hands.

properties in adequate degree for practical use, may form the scale.

In Figs. 6, 7 and 8 the flat sides are numbered 5, 5a and 5b, and the convex sides are numbered 6, 6a and 6b, respectively; and the recesses are numbered fl, and 1lb, respectively. Any of these recesses, as the recess l of Figs. l, 2, 3. 4

and 6, is formed to receive the bridge of the patients nose for supporting the scale on the nosey while the scale is held acrossv the eyes by For this purpose the recess is formed so that its top and sides recede upwardly from front to rear; the degree of this upward recession and the width of the recess being such that the recess will receive the most prominent and widest nose likely to be en- This meeting point is the base from whichr the measurements are taken in the opposite directions, for distances of the respective'pupils from lthis base point. The recess, having the `relation to the nose, substantially, that is to be had by the bridge piece of the eye glasses that are to be iitted, thus enablesV the operator to set f the scale so that the dimensions taken can be referredto the bridge piece of the glasses being made for the case. The extent of the recess sides along the nose adequately bases the scale on noses of different shapes and 'for rocking the scale front to rear for best view throughrthe scale.

All of the indicia are placed on the back 5 of the transparent prism, which, being flat except within Vthe recess 4, da or 4b, permitof more ready and accurate formation in the molding operation. What ismore important, the indicia are thus brought close to the eyes when the scale is set back astraddle of the nose, for maximum .Y

The setting of Vthe scale l accuracy o f reference. thus had is such that it magnies the4 pupils in upright direction to the right degree; butthe indicia being, in any of the examples, betweenA the focal line ofthe cylindrically, or approximately cylindrically, conforming prism and the front thereof, the indicia are not magnified nor distorted. It will be understood, therefore, that in all views except Fig. 2, the indicia are seen through the transparent prism; and that Fig. 2 shows the rear side with the indicia directly seen, with the numerals in reverse.

The upright line 1, meeting the top curve of the recess 4 at the point of tangency with the nose bridge, is the base line of the scale for the bridge-to-pupil measurements above mentioned. This line 'l assists the operator in setting the instrument at the tangent point. But the instrument is tiltable in the plane of its length, with the tangent point as the pivot. To enable the operatorv accurately to posture the instrument in this respect, the posture line 8 crosses the upright base line 1 at right angles at such height that,when the instrument is incorrect posture this line 8 'coincides with very limited areas at the inner corners of the eyes; the technical namefor such an area being canthus.

For any eye this area is approximately three millimeters below the average plane of Vthe pupils; variation'in any case being practically negligible. These areas are very readily recognized as definite reference points by the practiced Optometrist. rIhe tangent point on the nose bridge is designated a, the pupils l), and the reference points at the inner corners of the eyes,

`just mentioned, being designated c.

Not only do pupils b of the two eyes often have vdifferent distances from the middle line or point arof the nose, i. e., different monocular distances; often one pupil h is at agreater height than the other, withreference to the areas or canthi of' the respective eyes. It of course is important to construct the eye glasses so that the foci of the lenses will be correctly located relative to the pupils when the glasses are supported on the nose, `as to monocular distances from the nose bridge; but it is also important that the relation ofthe foci lto the pupils be correct in respect of altitude. For merely monocular measurement it is not so important that the scale be so accurately postured in the plane of its length as before mentioned; but for' the relative altitude measurements this correct posture in respect of some part of the structure surrounding the eye is important for insuring a'practically. correct measurement of the respective Aaltitudes of the pupils. Hence the posture line 8 as before described.

' In an area lying in front of the pupil when the scale is set in position, is a set of vertical lines or graduations S crossed by a set of. horizontal graduations ld, i. e., 'considering the scale to be set horizontally and without consideration of slight variations from the horizontal, according to the, congurationand posture of the head .of the patient. There is a set of these graduations 9 and l!) for each eye. As here shown a horizontal line of each set is succeeded upwardly and downwardly by two lines in each direction; there being thus five lines or `graduations, le in the set. Also, as here shown, sixteen vertical lines cross the horizontallines in each set of lines 9. rI'he metric system preferably is used, being the estab,- lished system for optical measurements; and it will be understood that the horizontal and vertical lines I and S indicate millimeters. Certain lines are more extended and have numbers, as 25, 30, 35 and 40 for the vertical graduations, indicating those numbers of millimeters from the base line l at the middle; and as 1 and 2 'for the horizontal lines or graduations, indicating those numbers of millimetersabove or below the middle horizontal line of the set, marked 0.

` For example of' use, in Fig. 3 the pupil b seen at the left is 3l millimeters from base line l', while pupil b seen at the right is millimeters frome base line l. Also, pupil b seenV at the left has the middle horizontal line through its center, so that it is noted as at zero altitude, While pupil b seen at the right has the next line up from the middle line through its center, so that it is noted as of altitude one up. Of course up may be noted as plus and down as minus altitude; it being understood thatY a prescription form may have the various measurements noted on it according to ,choice of the operator; From this prescription the optician proportions the mounting to fit in accordance` with the measurements given.

Along the edge portions of the recess d, 4a or 4b, are graduations basing from the upright base line 1, for measuring the width of the nose bridge. These graduations, designated Il, and here understood to be rnetrical as are the others before described, preferably are numbered in the oppoextent ofthe series beinglhere twelve.millimeters,l

their sum, twentysfour.vmillimeters, -beingl about the' maximum! nose'- brid'gefwidth encountered.

The dimensions thuslta'kenf Sarei noted so thatlth l opticianawillf f make'. .the` bridge-piece of the eye .glasses -rto Acorrectlyv locatef-thel lenses; -orJ their frames, with relationto themeseA bridge. i. ItiWi-ll beundestood-thatithieye glasses, mentioned as such anywhere herein, may be those with bows for the ears, either with or without articulated means to Contact thenose; or may be those that merely grip the nose, or pince nez, more. commonly called eye glasses, whereas those with bows are called spectacles. My invention is suited for measurements to guide the making of any eye glasses of any style or type, including those just mentioned.

Along the edge ofthe scale opposite to that having recess 4, lia or 4b, are graduations, metric in well known style, continuously numbered from l near one'end of the scale to near the other end;

in this case being'ifteen centimeters. These maybe used for binocular measurement, i. e., from one pupil to the other, as represented in Fig. 4; thus checking the two monocular measurements of Fig. 3--the total binocular against the sum of the monocular measurements. This scale also is useful for any other measurements,

with reference to the eyes, or to any thing else;

being a general .utility scale for the Optometrist in the manner of ordinary scales now used by "Lucite,before mentioned, a high degree of resistance to wear and scratching is had, more.

nearly comparable with such properties of glass; endurance under shocks, against breakage, is higher than that of glass; and the instrument is much lighter than would be one of glass, metal or the like, while the transparency and optical qualities compare Very favorably with those of the best optical glass, The shaping for magnification allows relief of strain ori the operator, by the elliptical enlargement ofthe pupils. Also it insures more accurate measurements, as the upright major axis oi the elliptical enlargement be estimated much more closely than can the mere diameter of the pupil, with no magnication. lThe measurements can be .taken to the edge of a pupil, if that is understood in the prescription; in which case the more nearly straight lateral edges of the elliptical magnifications can have the scale graduations related to them much more easily and accurately, compared with tangents of unmagniiied circular pupils. l

Reference of the relative altitude lines lil 4to the centers of the pupils is not impaired by the vertical enlargement, but is rather aided by the vertically elongated pupil image being vertically of greater extent than is the series of horizontal lines or graduations itt, so that the upper and lower ends of the elliptical pupilimage appear along'eachline 10d, numberedV as iin-the'previous example. These -graduations before i the i fpupils thus are the same except that lines above and below a base line, to which line Illa here corresponds, are omitted. Lines Iiib corresponding t0 such lines are arranged above and below the posture l-ine 8, and are numbered up and down, for reference to the eye corners or canthi when lines lila both are coinciding with their respective pupils. The `difference therefore is that the scale is tilted to aline with the pupils and the reading is made with reference to canthus locations V`that were` vused in the previous example to posture the scale to aline with those locations and the readingis made with reference to the pupils.

An advantage of having a transparent scale is the non-interference with the patients seeing, so that the patients pupils remain normally dilated, instead of contracting very considerably Y in the dark behind an instrument of opaque material. Of course this would be an advantage were the scale merely plano and not magnifying, if the scale were transparent with the other features -of my scale benefiting from the transparency.

Several modifications have been instanced, but it Will be understood that I am not limited to the rather precise disclosure herein, as to structure, materials or mode of us-e, but that what I claim as new and desire to secure by Letters Patent is:

1. A pupillary scale having va middle portion with an edge part shaped to straddle the nose for positioning said scale for use, and having lateral extensions to lie across the pupils when said scale is so positioned, said scale being transparent throughout said middle portion and its nose-straddling edge part and said extensions, ea-ch extension being, throughout its extent across Athe pupils when the scale is s0 positioned, of

substantially uniform upright cross section which has its outer side, remote from the pupils, convexly curve-d relative to its inner side, said mid? dle portion having index means refelable to a feature of the patient by View .through -said middle porition, and said extensions having, on their inner sides, index means referable to the pupils by view through said extensions, for definition of locations of said pupils relative to said feature, said denitions being facilitated by upright magnification of the pupils without substantial transacross the pupils when said scale is so positioned,

said scale being transparent throughout said middie portion and its nose-straddling edge part and the continuous structures of said extensions, said middle portion having a posture -line portion to be registered With eachcanth for definite- 1y posturing the scale, the line portions being Vreierable to said canthi by View through said transparent middle portion, and said extensions having respective upright series of indices, refer-- able to the pupils by View through the transparent structures of said extensions, for denition ofthe altitude of each pupil relative to said posture line portions.

. `WILLIAM R. HEARN., 

